New AC Delco compressor stiff, but everything works

[A_User55555]

I just had a new OEM AC Delco AC compressor installed on my car. The old one wasn’t internally bad just had a bad pulley and clutch

With my mechanic, we took the new one out of the box, and noticed it was stiff but able to turn by hand

Meanwhile the old compressor was easier to turn. You could turn the shaft with your fingers and without the clutch plate.

I decided to install it. Vacuumed system and recharged it with the proper R134a.

Everything works great. The temps go down to 45deg F on an 84degree day and there’s no loud noises from the compressor when the AC is engaged

But when I reach under the hood and try to turn the clutch plate, I can’t do it. It’s too hard. But the engine turns it fine. It’s not slowing down my engine either.

Should I stop using the AC and maybe swap the compressor again? Or am I just overthinking things? I’m worried this might grenade itself.

 

[Chevyc10]

Did you add oil to compressor ? Most don’t come with oil. You add oil and turn compressor by hand to circulate oil before installing.

 

[JavierH19]

A lot of them say to hand turn to distribute oil around first.

 

[A_User55555]

Did you add oil to compressor ? Most don’t come with oil. You add oil and turn compressor by hand to circulate oil before installing.

Yes we added the right amount of PAG oil

 

[A_User55555]

A lot of them say to hand turn to distribute oil around first.

We did that. The sticker said there was 24CC of oil in it. But when we turned the pulley, nothing came out. It seemed dry. So we did the oil balance and added the right amount back.

 

[Ausfahrt]

Without being there that sounds normal and nothing to worry about.

 

[JavierH19]

We did that. The sticker said there was 24CC of oil in it. But when we turned the pulley, nothing came out. It seemed dry. So we did the oil balance and added the right amount back.

In that case I'm sure it's fine. I guess it just needs to break in.

 

[atikovi]

The old one was weak and had low compression. The new one is strong with good compression, hence hard to turn by hand.

 

[A_User55555]

Ok small update.

Now when the car is “cool” or sitting a few hours, then I can turn the compressor by hand smoothly. Before it was always stiff even new in the box. Maybe it broke in or absorbed some PAG oil

But after running the AC for a few minutes, the compressor gets “stuck” I can’t turn it at all by hand.

However if the engine turns the AC compressor then it seems ok.

RPMs don’t dip
Tensioner isn’t wobbling
Belt isn’t squeaking
Small loss of MPG
No noise in the interior
No noise from the compressor

And the AC always blows cold (44 deg vent temp)

Sometimes I get the impression that the engine is working hard to turn the compressor, but I could just be overthinking

Either the “stiffness” is from the refrigerant pressure, or due to excess friction in the piston rings. Hard to tell.

 

[clinebarger]

New compressors have far more rotational resistance.

 

[repairman54]

After running and trying to turn by hand it will be stiff. Sitting lets the high and low side pressures equalize so less high side pressure and resistance. Normal.

 

[KrisZ]

A new compressor will be harder to turn as it seals better and has more compression.

You would notice a similar thing with a brand new engine vs one with 200k miles.